DAMASCUS, Syria (CNN) -- The leaders of Syria and Lebanon have announced the pullback of Syrian troops to Lebanon's eastern Bekaa Valley by the end of March.

Syrian President Bashar Assad and Lebanese President Emile Lahoud, in a statement following their meeting Monday in Damascus, did not say when the pullback would begin nor how many troops would be involved.

At a meeting in Damascus, Assad and Lahoud committed to the first stage of withdrawal and made plans for the second stage, under which Syria will move all 14,000 troops back into Syrian territory.

Opposition leaders expressed some hope but demanded full, immediate withdrawal. And the White House -- which has been leading an international effort to push Syria out of Lebanon -- called it "a half measure that does not go far enough."

Assad and Lahoud issued a communique at the end of their meeting, saying the initial move will take place "before the 30th of March 2005." Then, a joint military commission will have one month to meet and work out the next phase of the withdrawal.

"At the end of the Syrian troops presence ... both the Lebanese and Syrian governments will agree to the complete withdrawal of the remaining Syrian troops," the document said.

By late Monday, some troops had already begun to move to the Bekaa Valley, traveling along a highway lined with Lebanese troops.

Assad announced plans for the two-stage pullback Saturday in an address to his parliament. He said the troops in Lebanon would be relocated to the Bekaa Valley, and then later to the borderline -- but he did not say which side of the border. Syrian Cabinet minister Bouthaina Shaaban later told CNN the troops would be moved to the Syrian side of the border.

In an interview with CNN after the communique was released Monday, Syrian Ambassador to the United States Imad Moustapha said the pullback to the Bekaa Valley will happen "very soon -- in less than two or three weeks," and "all of our troops" will then be moved "into Syria itself."

Asked whether that will include Syrian intelligence personnel , he nodded his head and said, "Everybody. Everybody."

Opposition leader Nassib Lahoud said of the plan, "Thirteen years ago this would have been acceptable." Now, he said, "the people of Lebanon" want "a timetable for full withdrawal from Lebanon."

He said the opposition wants "full withdrawal within a matter of weeks."

But Walid Ido, an opposition member of parliament, said, "I welcome this step of the withdrawal, which came not under the name 'redeployment' but 'full withdrawal.'"

At an anti-Syrian rally in Beirut, one participant called Monday's agreement "the beginning of the independence of Lebanon." There have been daily protests in Lebanon, with tens of thousands of people calling for the ouster of Syrian forces, since the assassination three weeks ago of opposition leader and former prime minister Rafik Hariri. The pro-Syrian Lebanese government resigned amid the pressure.

World leaders including President Bush have called for Syria to immediately withdraw all its troops and intelligence officials. White House officials said the Bush administration wants Syria out of Lebanon before Lebanese parliamentary elections in May.

At a daily briefing Monday with reporters, White House spokesman Scott McClellan called Monday's deal "a half measure that does not go far enough.

"It is time for Syria to fully implement United Nations Security Council Resolution 1559. That means the complete and immediate withdrawal of all Syrian military forces and all intelligence services from Lebanon."

He added, "The Lebanese people are showing their desire to live in freedom and sovereignty and independence, free from outside interference and intimidation. And we want to see the Syrian and Lebanese government respect the will of the Lebanese people."

He said the United States and the "international community" stand with the Lebanese people "as they work to build a democratic future."

German Chancellor Gerhard Schroeder and French President Jacques Chirac released a joint declaration Monday saying their two nations "reinforce their support for an independent, sovereign and democratic Lebanon."

Syrian officials told CNN they are following U.N. Resolution 1559 as well as the Taif Accord, signed in 1989, which legitimized Syrian presence in Lebanon at the end of a bitter civil war there but called for a later withdrawal.

The Lebanon-based Shiite Muslim militant group Hezbollah, which has support in Syria, called for a major pro-Syrian protest Tuesday in Beirut, focusing largely on condemnation of Israel. Many Arabs see Hezbollah as heroic for helping drive Israeli forces from Lebanon.

Hezbollah has carried out numerous terrorist attacks against civilians and is listed by the United States and Israel as a terrorist organization. It remains an official party in Lebanon.

U.S. officials have called on both Lebanon and Syria to halt support for Hezbollah.

In addition to calling for the ouster of foreign forces from Lebanon, U.N. Resolution 1559 also called for "the disbanding and disarmament of all Lebanese and non-Lebanese militias" -- which includes Hezbollah.

The resolution said the Security Council is "gravely concerned at the continued presence of armed militias in Lebanon, which prevent the Lebanese government from exercising its full sovereignty over all Lebanese territory."